心力衰竭的病人和正常人相反,在乏氏动作的用力期保持动脉压和脉压不变,提示左心室每搏输出量恒定。此可能有二个机制:(1)受损的左心室在心脏功能曲线的平台期工作,尽管在乏氏动作用力期左心室舒张末压下降,而每搏输出量不变,这一作用因胸内压增加导致有效后负荷下降而得到加强。(2)心力衰竭病人在乏氏动作用力期左心室舒张末期容量可能维持不变,以致每搏输出量不变。为探讨上述机制的可能性,作者对正常志愿者 Contrary to normal subjects, patients with heart failure maintain constant arterial pressure and pulse pressure during the period of fatigue, suggesting that the left ventricular stroke volume is constant. This may have two mechanisms: (1) impaired left ventricular function in the plateau phase of cardiac function, despite the fatigue during the exercise of left ventricular end-diastolic pressure decline, while the stroke volume constant, the role of Increased intrathoracic pressure leads to a reduction in effective postload. (2) The volume of left ventricular end-diastolic volume in patients with heart failure during the exertion of fatigue may remain the same, so that the stroke volume will not change. To explore the possibility of the above mechanism, the author of normal volunteers